Method of preventing staining of veneers in veneer slicers



L. J. KOSS April 29, 1969 METHOD OF PREVENTING STAINING OF VENEERS INVENEER smcERs Sheet Original Filed March 8, 1965 III/IIIIIIIIIIIIIII/IIIIl/IIIIA IFI Er." l

HNVENTUR LUUIS JACK KUSS ATTCLENEX.

L. J. KOSS A ril 29, 1969 METHOD OF PREVENTING STAINING OF VENEERS INVENEER SLICERS Z of 4 Sheet Original Filed March 8, 1965 N m E JINVENTDRLUUIS JACK KUSS MQ MAW ATTORNEY L. J. KOSS April 29, 1969 METHOD OFPREVENTING STAINING OF VENEERS IN VENEER SLICERS Sheet 3 014 OriginalFiled March 8, 1965 km W LDUIS qzuzx K055.

ATIJLBNEY L. J. KOSS April 29, 1969 METHOD OF PREVENTING STAINING OFVENEERS IN VENEER SLICERS original Filed March a, 1965 Sheet ATTURNEY.

United States Patent 3,441,069 METHOD OF PREVENTING STAINING 0F VENEERSIN VENEER SLICERS Louis Jack Koss, Indianapolis, Ind., assignor toCapital Machine Company, Inc., Indianapolis, Ind. Continuation ofabandoned application Ser. No. 437,744, Mar. 8, 1965. This applicationJuly 12, 1967, Ser. No.

Int. Cl. B271 /00,- B27c 1/14 US. Cl. 144-309 3 Claims ABSTRACT OF THEDISCLOSURE The method of prevention of blue stain or the like in thecutting of wood veneer by holding the temperature of the cutting knifeand the pressure bar of a veneer cutting machine above the dew point ofwater at ambient temperatures.

This is a continuing application from applicants copending applicationSer. No. 437,744, filed Mar. 8, 1965, and now abandoned.

This invention is concerned primarily with avoidance of staining veneerin its slicing from a rotating log or a reciprocating flitch, either ofwhich have been previously soaked in water until its temperatureuniformly throughout has approached or equalled that of the water whichis maintained at a temperature near the boiling point of the water. Forhardwoods, this temperature is 200 degrees F.

Included in hardwoods are oak, walnut and cherry, from which the mostexpensive veneers are cut. Such woods have more acid content and aremore prone to stain veneer than are the softwoods including birch. Thewater content of the woods is acid in reaction, the hardwoods being morehighly acid than are the less expensive softwoods.

These acids cause a blue staining of the veneer when the log-carriedacidified water is permitted to contact the cutting knife and pressurebar and drip or flow therefrom onto the veneer. When this acidifiedwater comes into contact with the knife and bar, normally having an ironcontent, an iron salt is formed. The temperatures of the knife and barparticularly in cool or cold atmospheres are such that, when themoisture from the log or in the veneer, or both, picks up thissurface-formed iron salt and deposits it on the veneer, blue stainsresult.

When the veneer, such as walnut, is cut with a thickness of one-fiftiethof an inch, the stain will extend entirely through the veneer and noamount of sanding will remove it. The presence of this blue stain innormally high priced walnut renders the veneer virtually worthless. Bothoak and walnut are in short supply and the supply is getting shorter.

The wood temperature, being above that of the atmosphere, sets up twoproblems as set out in my original application.

One problem is that of heat induced distortion of the cutting knife andpressure bar which produces varying thicknesses of the veneer, and theother problem which is that of staining the veneer.

The rmult of the first problem may possibly be overcome by sanding ofthe veneer to a uniform thickness, but may be avoided by heating theknife and bar.

The solution of the second problem of veneer staining is necessary,since the stain, generally a blue stain, extends entirely through theveneer and cannot be sanded out and cannot be used in furniture makingor in other products where the stain blemish is visible and creates anunsaleable situation. In other words, stain-free vener is required. Toinsure its production, the problem has been 3,441,069 Patented Apr. 29,1969 solved by proceeding oppositely from the solution to overcome knifeand bar distortions.

My method of avoiding the veneer staining resulting from the wood acidcontent and iron content of the cutting knife and pressure bar may bepracticed by different forms of apparatus, one particular apparatusbeing that shown in the accompanying drawing, in which:

FIG. 1 is a view in vertical cross section of a veneer slicing machine,to which my invention is applied;

FIG. 2 is a fragmentary view of an enlarged scale in vertical elevationof the knife side of the knife carrier of the machine;

FIG. 3 is a view in end elevation of the knife carrier;

FIG. 4 is an end view in partial section of a pressure bar carrier;

FIG. 5 is a vertical, transverse section of a knife carrier employing amodified form of the invention;

FIG. 6 is a similar section on a reduced scale showing a still furthermodified form;

FIG. 7 is a view in inside vertical elevation of a knife heat equalizerand transfer plate;

FIG. 8 is a vertical section on the line 88 in FIG. 7; and

FIG. 9 is a diagram of a heating control and heat transfer fiuidcirculating system.

Referring first to FIG. 1, the view is that of a portion of a veneerslicing machine, the total weight of which machine will be several tonsin addition to the flitch Weight. The flitch 10 is dogged to a table 11which is reciprocated diagonally across a number of guide frames one ofwhich being designated by the numeral 12-carried on a bed 13.

Also carried on the bed 13, is a carriage 14, slidably shiftable towardand away from the path of the flitch. A knife and pressure bar carriergenerally designated by the numeral 15 is rockably supported by abearing shaft 16 on the carriage 14.

The knife bar 17 is secured detachably to the carrier 15 to present acutting edge 18. The carrier 15 is rocked to bring this edge 18 into andout of veneer slicing operation and suitable mechanism (see Patent No.2,303,213), is supplied to rock the carrier in precise relationship tothe travel of the table '11, such mechanism being old and forming per seno part of the present invention. The pressure bar 19 is mounted alongthe rear edge 20 of a carriage 21 to be adjustably slidably carried byits underside 22 on the surface 23 of the knife carrier 15, FIGS. 3 and4, so as to be able to secure the proper positioning of the bar 19 inrelation to the knife edge 18.

The description of the veneer slicing machine so far presented is oldand has been incorporated in machines made for many, many years past, atleast as early as in the year 1904, as indicated and described in US.Patent No. 793,306, and in the later US. Patent No. 2,303,213 of 1942,the patentees of both patents having been relatives of the applicantherein.

It is to the foregoing described structure, as one particular example,that applicant applies his invention.

The knife bar carrier 15 is provided with a planar face 24 extendingthereacross and having a transverse width slightly less than the Widthof the knife bar 17. A pair of laterally spaced apart slots or grooves25 and 26 are formed to extend back of the face 24 and therealong for amajor length of the face 24.

A cover plate 27 is shaped to have approximately parallel, major lengthsides 28 and 29, and approximately parallel ends 30 and 31. The plate 27has a planar face 27a placed over the face 24 and is provided with acontinuous groove 32 roughly in the shape of an ellipse. This groove 32has its sides and ends spaced apart to be beyond the confines of thegroves 25 and 26. A resilient sealing ring 33 in the nature of an O-ringfits in the plate groove 32 and bears against the face 24 when the plate27 is brought up theretoward. Fluid is to be circulated into and out ofthese grooves 25 and 26. The plate 27 and ring 33 forms a sealpreventing fluid leakage beyond the confines of the ring 33.

Though the groves 25 and 26 may be interconnected in series, they areillustrated as being connected in parallel, FIG. 2. The carrier 15 isbored as by bores 34 and 35 to intersect respectively end portions ofthe grooves 25 and 26 as illustrated, FIG. 2. Tubes 36 and 37 connect tothe respective bores, one extending along behind the carrier portionsupporting the knife bar as a length 37a to approach the other tube 36.

Likewise, FIG. 4, the pressure bar carriage 21 is provided withlongitudinal grooves 38 and 39 on the one side of the bar 19, and agroove 40 on the underside somewhat to the rear of the bar 19. Tubes 41,42 and 43 such as copper, are held in these respective grooves 38, 39and 40. The tube 41 is connected toward one end with an inlet tube 44and a tube 45 interconnects the tube 41 with the tube 42. A return tube46 leads from the tube 42 at a zone remote from the tube 45. The tube 43is interconnected with the tubes 44 and 46 by the end tubes 47 and 48.

Fluid (water being suflicient if it carries an anti-freeze ingredientwhen the veneer slicer may be exposed to below freezing temperatureswhen not operating) is conditioned as to its temperature and circulatedby some device auotmatically controlling the temperature under a widerange of slicer operating conditions. One such device isdiagrammatically illustrated in FIG. 9. This particular device iscommercially obtainable. It is manufactured by Industrial ManufacturingCorp, of Indianapolis, Indiana, and sold under the US. registeredtrademark Thermolator. The device is not claimed per se.

The tubes 46 and 47 are interconnected with the tubes 37 and 36respectively. These tubes 36 and 37 lead to the temperature controllingdevice which is generally designated by the numeral 50. A water heatertank 51 carries internally an electric heating element 52 havingexternal supply wires 53, 54. A water service pipe 55 under normalservice supply pressure connects through a check valve 62 to athermostat 63. The check valve 62 serves to prevent reverse flow.

The tank 51 is provided with an automatic air vent 57 which is connectedwith a pipe 58. An automatic pressure relief valve 59 is mounted betweenthe tank 51 and the overflow pipe 58. A second automatic relief value 60is connected to the tank 51 and opens at a higher pressure than isrequired to open the valve 59. For example, the valve 59 may be set toopen at 100 pounds per square inch, and the valve 60 be set to open at125 pounds. A solenoid operated valve 61 is provided to interconnect thetank 51 directly to the overflow pipe 58.

The thermostat 63 operates to control the operation of heating element52. A circulating pump 66 takes water from the tank 51 and flows thewater through the tube 36 to the knife bar and pressure bar heattransfer tubes. A portion of the pump discharge is by-pas'sed throughthe pipe 67, through an orifice unit 68 to reduce water flow. Theby-pased water flows across an auxiliary electric heating element 80,mixing with the water from the pipe 62, and the resultant tempered waterdischarges through the pipe 64, and the pipe 64 into the tank 51. Thethermostat 63 serves to control through suitable circuitry the majorheating element 52, such circuitry not entering per se into myinvention.

The temperature of the outfiowing water into the pipe 36 is thuscontrolled by the device to maintain through heat transfer between thewater and the knife 17 and the pressure bar 19 an approximately constanttemperature above the dew point of water at the ambient temperaturewhereby, condensation of moisture on the knife or pressure bar or thecarriers is prevented and, in the absence of temperature variation,there is no temperature change induced warping, distortion of thosemembers, and change in dimensions thereof is inhibited.

The grooves 25 and 26 cut in the carrier 23 carry the water to be indirect contact through the cover plate 27 and the knife 17 is in directcontact over the face of the plate 27 and there secured by bolts 70extending through the plate 27 and screw-threadedly engaging in thecarrier 23. The plate 27 is initially attached to the carrier by screws71. Thus, the plate 27 serves as a heat transfer medium.

As shown in FIGS. 4, 5 and 6, tubes of a material of good heatconduction are inserted within grooves cut from the faces of thepressure bar carrier, or the knife carrier. These tubes in this form aregenerally designated by the numerial 75. These tubes are imbedded in aplastic 76. Heat conducting elements, such as bits of copper or aluminumare mixed in the plastic to improve the heat transfer. A thinner coverplate 77 may be used as in FIG. 5, to protect the tubes 75 and theplastic 76 in changing knives 17. However, this plate may be omitted andthe knife 17 be pressed directly against the face 24, thus providingapproximately no distance between the tubes 75 and the knife 17 therebyhaving the maximum rate of heat transfer to the knife, FIG. 6.

In this heat exchange system the system is always under pressure inducedby the service supply. No water will normally be wasted. The cover plate27 is made out of metal such as the so-called stainless steel, an alloyof aluminum or the like, so that the plate will be a good heatconductor, and the heat fromthe water whether carried in one or aplurality of grooves or tubes may transfuse to bring the entire knife upto the predetermined working temperature and not have the knife to haveradically varying temperatures throughout both its width and length.When the plate 27 may be omitted, the carrier itself serves to diffusethe heat over said area. Since the two carriers are preferably made ofcast iron and of considerable mass, the mass adjacent to the knife whenonce brought to the desired temperature, will tend to maintain thattemperature and radiate the heat through the knife bearing areas. Theknife, of course, is made out of a high grade of steel such as will holdits cutting edge for hours of usage.

In employing the apparatus described, the temperature of the water beingcirculated is maintained to maintain the temperature of the cuttingknife 17 and of the bar 19 above the dew point of water at the ambienttemperature. In other words, my method in preventing the veneer stainingis to prevent the water from the log from condensing on cold metal andflowing onto the veneer. The log-contained water will normally not befree flowing therefrom and the percentage of water contained in the logwill be the same in the veneer. If the metal knife and bar be below thedew point of water, then the moist surface of the log and veneer cominginto contact with the colder knife and bar will condense thereon. Whenthe knife and bar are at temperatures above that which would otherwiseinduce water condensation, the knife and bar remain dry. Hence, by theexpedient of maintaining a dry knife and pressure bar, there is nostaining.

I claim:

1. A method of obtaining water-stain free veneer being cut in a machinebetween a knife and a pressure bar from a hot, water-soaked log, whichmethod comprises the steps of circulating a fluid adjacent said knifeand said bar, and maintaining an intimate heat-exchanging relationbetween the knife and the fluid and between the bar and the fluid, saidfluid being conditioned to a temperature such as to maintain the knifeand the bar at temperatures above the dew point of water at ambienttemperatures.

2. A method of obtaining water-stain free veneer being cut in a machinebetween a knife and a pressure bar from a hot, water-soaked log, whichmethod comprises the steps of supplying heat to the knife by moving aheated fluid in heat-exchanging relation to said knife and supplyingheat to the pressure bar by moving a heated fluid in heat-exchangingrelation to said pressure bar, while maintaining the temperature and therate of movement of such fluid at values suflicient to hold thetemperature of the knife and of the pressure bar above the dew-point ofwater at the ambient temperature. 1

3. A method of obtaining water-stain free veneer being cut in a machinebetween a knife and a pressure bar from a hot, water-soaker log, whichmethod comprises the steps of moving a heated fluid in heat-exchangingrelation to said knife and moving a heated fluid in heat-exchangingrelation to said pressure bar, While maintaining the temperature and therate of movement of such fluid at values suflicient to prevent drip ofcondensate from the knife or from the pressure bar onto the veneer.

References Cited UNITED STATES PATENTS 3,265,103 8/1966 Hervey 144-178GERALD A. DOST, Primary Examiner.

US. Cl. X.R. 144-178

